I. Field of the Invention:
This invention relates generally to radar detection apparatus, and more particularly to an apparatus and method for extracting high resolution information from radar return signals, whereby a target can be readily discriminated in a high clutter background to the extent that the target is susceptible of classification.
II. Discussion of the Prior Art:
In modern weaponry, there is a need for a "seeker" on a missile or projectile which can home in on a target and guide the missile or projectile to it. Such a seeker must operate in all weather conditions as well as in the presence of high levels of smoke and dust particles. Applicants' assignee has demonstrated that millimeter wave radar (MMW radar) can be embodied in such seekers to detect and track practical targets in low to moderate ground clutter conditions.
A major problem with MMW radar-based seekers is the degradation of the target discrimination capability where the ground clutter is more than what can be considered "moderate". More particularly, high clutter levels tend to result in excessive false-alarm rates where the MMW radar seekers depend only upon contrast differences to identify the presence of a target within the background clutter.
All weather MMW radar terminal guidance seekers have been under development for several years. It is a requirement of such seekers that they operate in a lock-on-after-launch mode to permit maximum operational flexibility. During the autonmous search and acquistion period, the signal processor involved must look at many radar returns from high clutter sources or from other non-target objects which, of course, must be rejected by the signal processor. It has been found that standard contrast detection processing is inadequate to ensure target discrimination in a high clutter environment. A normal MMW radar exhibits a resolution which is larger than many of the enemy targets to be destroyed. For example, a radar-based seeker of the prior art may typically have a resolution on the order of 10 meters. Such a resolution factor is insufficient to adequately select a man-made target, such as a tank or other weapons carrier, from the background and clutter which may surround the vehicle target in question.